////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2009 Daniel F. Hanson
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
////////////////////////////////////////////////////////////////////////////////

using System.Collections.Generic;

namespace SilverLua.Compiler
{
   internal class SymbolTable
   {
      internal List<ChunkScope> Chunks { get; private set; }
      
      private Stack<ChunkScope> _chunkStack = new Stack<ChunkScope>();

      internal ChunkScope CurrentChunk { get { return _chunkStack.Peek(); } }
      
      internal void Initialize()
      {
         Chunks = new List<ChunkScope>();
         
         ChunkScope chunk = new ChunkScope();
         Chunks.Add(chunk);
         _chunkStack.Push(chunk);
      }
      
      internal int PushChunk()
      {
         int chunkIndex = Chunks.Count;
         ChunkScope chunk;
         
         if (_chunkStack.Count == 0)
         {
            chunk = new ChunkScope();
         }
         else
         {
            chunk = new ChunkScope(_chunkStack.Peek());
         }
         
         Chunks.Add(chunk);
         _chunkStack.Push(chunk);
         return chunkIndex;
      }
      
      internal void PopChunk()
      {
         _chunkStack.Pop();
      }

      internal void PushBlock()
      {
         _chunkStack.Peek().PushBlock();
      }

      internal void PopBlock()
      {
         _chunkStack.Peek().PopBlock();
      }
   }
}
